<button>点击</button>
<script>
    //动态创建
    var s = document.createElement("script");
    s.src = "http://localhost:3000/s?wd=fun";
    document.body.appendChild(s);
</script>
<script>
    function fun(q) {
        console.log(q);
    }
    //fun("这是服务器发送的内容")
</script>